The present invention relates to an improved hard static balancing machine. Static balancers are machines designed to determine the balance of a rotating workpiece without the necessity of actually spinning the workpiece.
A hard static balancer is a balancer which has a hard suspension. In this type of a balancer, only minute deflections results from the unbalance. This deflection is transferred to a force transducer which is capable of directly reading unbalance movement with the negligible deflection.
A discussion of prior art static balancing machines is provided in U.S. Pat. No. 4,467,650, which is incorporated herein by reference.
The hard static balancer of the above-identified U.S. Pat. No. 4,467,650 incorporated a single element flexure pivot for providing workpiece support while permitting tilting movement of the workpiece around a vertical axis. A pair of linear variable differential transformers (LVDTs) were utilized to receive and measure the unbalance effects from workpiece displacement. Restoring springs were provided to return the transmitting member to a zero or home position upon removal of the workpiece.
It has been found that the incorporation of a linear variable differential transformer (LVDT) into a static balancing machine sometimes results in a balancer which is difficult to return to its home position. The core of the LVDT is attached to the central transmitting member. The body of the LVDT which normally includes a primary coil and two secondary coils is initially carefully positioned with respect to the core to avoid physical contact and to obtain the null or home reading on the electric readout control panel.
If the ambient temperature within a factory setting varies greatly, it is often difficult to adjust the LVDT to return the readout to its home position.